Railways are subject to the effects of the weather and are built to withstand natural hazards. There is a wide understanding that the observed extreme weather of today could become the "normal" weather of tomorrow, and because it is widely accepted that the consequences of climate change are advancing, there is an already present need to develop and implement adaptation strategies and measures for transport systems and railways. Also, the importance for railways is not only to withstand extreme weather conditions, but also to recover from them in a short time and to be able to run in what are more extreme circumstances today.
In recent years, Climate change has received increasing global attention and has appeared on global and national political agendas. There is a growing pressure on society as a whole, and especially on governments and companies, to learn more about the cause and the effects of global warming and how to cope with it.
The challenge for railways is not only to survive extreme weather conditions, but also to recover quickly from them and to be able to run in what are abnormal circumstances today.
Objectives and main outputs of the project
Case studies provide an excellent framework to investigate and assess the effects of different early and late adaptation measures in comparison to zero adaptation on a real network and infrastructure. Central tasks will be the identification of most endangered assets and locations by means of vulnerability mapping, the detailed analysis of specific adaptation measures and related costs for these assets and the concrete options for the adaptation of standards.
The most vulnerable locations and assets we are confronted with during extreme weather situations are only rarely totally new. In most cases they are the ones where problems have already occurred in the past and where more problems are to be expected in the future. Therefore, collecting and analysing this information from past major weather events is already a good first step towards identifying hot spots. A second step involves mapping activities using regional climate models and provides the basis for identifying possible mid- and long term hot spots. One should keep in mind that return periods are location specific and will in the long run very likely go down due to climate change.
Since the majority of lines in most networks is quite robust regarding extreme weather situation and only a few cause the big problems it makes sense not to aim at 100% coverage in the case studies but to concentrate on critical locations and assets. If these are related to very old infrastructure assets the rebuilding should already enhance their resistance and, thus, performance since they are rebuild using current engineering standards. Nevertheless it should be checked by means of a risk assessment if the upgrading to actual standards and the chosen performance level are appropriate in the long run and will lower the vulnerability significantly.
It is also very important: to keep the system approach and to find the appropriate performance level! Even if new infrastructure (at critical locations) is designed to withstand e.g. a 200 year flood, every year or couple of years a single event will knock one or more routes out. So the challenge is to make a whole route or network more robust instead of focusing only on single sites and find at the same time an affordable solution (balance!). An important aspect to investigate in this respect is the appropriate level of redundancy in a system for an optimum robustness at affordable costs.
A very important focus of the project and especially the case studies is costs and affordability! A leading question is how to adapt a given railway network within a timeframe of the next 30 years to the consequences of Climate change at reasonable costs and effort. It has to be analysed if an early intensified adaptation during a transition period (next 15 – 20 years) avoids later excessive repair and adaptation costs.
In addition to costs and affordability effects on availability (disturbances) and safety have to be considered. Adaptation to climate change should be seen in this threefold perspective. The expected impacts of different adaptation strategies on availability and safety could be an important argument for early adaptation measures and for consequent adaptation programs. All these aspects should be covered by means of systematic risk assessments.